/*
  Copyright (c) 2011 Arduino.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "itoa.h"
#include <string.h>

#ifdef __cplusplus
extern "C"
{
#endif // __cplusplus

#if 0
/* reverse:  reverse string s in place */
static void reverse(char s[])
{
  int i, j ;
  char c ;

  for (i = 0, j = strlen(s) - 1 ; i < j ; i++, j--) {
    c = s[i] ;
    s[i] = s[j] ;
    s[j] = c ;
  }
}

/* itoa:  convert n to characters in s */
extern void itoa(int n, char s[])
{
  int i, sign ;

  if ((sign = n) < 0) {  /* record sign */
    n = -n;          /* make n positive */
  }

  i = 0;
  do {
    /* generate digits in reverse order */
    s[i++] = n % 10 + '0';   /* get next digit */
  } while ((n /= 10) > 0) ;     /* delete it */

  if (sign < 0) {
    s[i++] = '-';
  }

  s[i] = '\0';

  reverse(s) ;
}

#else

  static void reverse(char *begin, char *end)
  {
    char *is = begin;
    char *ie = end - 1;
    while (is < ie)
    {
      char tmp = *ie;
      *ie = *is;
      *is = tmp;
      ++is;
      --ie;
    }
  }

  extern char *itoa(int value, char *string, int radix)
  {
    return ltoa(value, string, radix);
  }

  extern char *ltoa(long value, char *string, int radix)
  {
    char tmp[33];
    char *tp = tmp;
    long i;
    unsigned long v;
    int sign;
    char *sp;

    if (string == NULL)
    {
      return 0;
    }

    if (radix > 36 || radix <= 1)
    {
      return 0;
    }

    sign = (radix == 10 && value < 0);
    if (sign)
    {
      v = -value;
    }
    else
    {
      v = (unsigned long)value;
    }

    while (v || tp == tmp)
    {
      i = v % radix;
      v = v / radix;
      if (i < 10)
      {
        *tp++ = i + '0';
      }
      else
      {
        *tp++ = i + 'a' - 10;
      }
    }

    sp = string;

    if (sign)
    {
      *sp++ = '-';
    }
    while (tp > tmp)
    {
      *sp++ = *--tp;
    }
    *sp = 0;

    return string;
  }

  extern char *lltoa(long long val, char *result, int base)
  {
    if (base < 2 || base > 16)
    {
      *result = 0;
      return result;
    }

    char *out = result;
    long long quotient = val > 0 ? val : -val;

    do
    {
      const long long tmp = quotient / base;
      *out = "0123456789abcdef"[quotient - (tmp * base)];
      ++out;
      quotient = tmp;
    } while (quotient);

    // Apply negative sign
    if (val < 0)
      *out++ = '-';

    reverse(result, out);
    *out = 0;
    return result;
  }

#if __GNUC__ > 4 || (__GNUC__ == 4 && (__GNUC_MINOR__ > 9 || \
                                       (__GNUC_MINOR__ == 9 && __GNUC_PATCHLEVEL__ > 2)))
  extern char *utoa(unsigned value, char *string, int radix)
#else
  extern char *utoa(unsigned long value, char *string, int radix)
#endif
  {
    return ultoa(value, string, radix);
  }

  extern char *ultoa(unsigned long value, char *string, int radix)
  {
    char tmp[33];
    char *tp = tmp;
    long i;
    unsigned long v = value;
    char *sp;

    if (string == NULL)
    {
      return 0;
    }

    if (radix > 36 || radix <= 1)
    {
      return 0;
    }

    while (v || tp == tmp)
    {
      i = v % radix;
      v = v / radix;
      if (i < 10)
      {
        *tp++ = i + '0';
      }
      else
      {
        *tp++ = i + 'a' - 10;
      }
    }

    sp = string;

    while (tp > tmp)
    {
      *sp++ = *--tp;
    }
    *sp = 0;

    return string;
  }
#endif /* 0 */

  extern char *ulltoa(unsigned long long val, char *result, int base)
  {
    if (base < 2 || base > 16)
    {
      *result = 0;
      return result;
    }

    char *out = result;
    unsigned long long quotient = val;

    do
    {
      const unsigned long long tmp = quotient / base;
      *out = "0123456789abcdef"[quotient - (tmp * base)];
      ++out;
      quotient = tmp;
    } while (quotient);

    reverse(result, out);
    *out = 0;
    return result;
  }

#ifdef __cplusplus
} // extern "C"
#endif // __cplusplus
